[R6RS] Case-sensitivity

[Anton van Straaten]

Michael Sperber wrote:
> I'm concerned about our decision to make Scheme case-sensitive.
> So---do you agree we should have a rationale on this?  If so, what is
> it?

I agree that it would be useful to have an "official" rationale 
available, even if it's not in the R6RS itself.

Although I usually prefer to work in a case-insensitive language, I 
don't think that simply sticking with case-insensitivity would be good 
enough.  For example, case-sensitive symbols in Scheme programs are 
necessary when working with case-sensitive XML data using SXML.  The 
same goes for any other embedded sublanguage which maps to some 
case-sensitive external language.

Ideally, I would like to see a standardized way to choose between the 
two options, such as the #cs and #ci expression markers in PLT.

I had previously thought that requiring support for both modes might be 
too demanding as a requirement for R6RS.  However, on c.l.scheme today, 
Jens Axel Søgaard raised another issue:

> From an implementation point I don't think it is an either-or. In
> order to support r5rs-code, implementations need to keep some kind of
> case-insensitive mode. 

At least in the short term, then, implementations are likely to support 
both, which makes me think that standardizing the mechanism for choosing 
between modes could make sense.

Anton